<?php

/*
 * This file is part of SwiftMailer.
 * (c) 2004-2009 Chris Corbyn
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

/**
 * Handles Quoted Printable (QP) Encoding in Swift Mailer.
 *
 * Possibly the most accurate RFC 2045 QP implementation found in PHP.
 *
 * @package    Swift
 * @subpackage Encoder
 * @author     Chris Corbyn
 */
class Swift_Encoder_QpEncoder implements Swift_Encoder
{
	/**
	 * The CharacterStream used for reading characters (as opposed to bytes).
	 *
	 * @var Swift_CharacterStream
	 */
	protected $_charStream;

	/**
	 * A filter used if input should be canonicalized.
	 *
	 * @var Swift_StreamFilter
	 */
	protected $_filter;

	/**
	 * Pre-computed QP for HUGE optimization.
	 *
	 * @var string[]
	 */
	protected static $_qpMap = array(
		0 => '=00', 1 => '=01', 2 => '=02', 3 => '=03', 4 => '=04',
		5 => '=05', 6 => '=06', 7 => '=07', 8 => '=08', 9 => '=09',
		10 => '=0A', 11 => '=0B', 12 => '=0C', 13 => '=0D', 14 => '=0E',
		15 => '=0F', 16 => '=10', 17 => '=11', 18 => '=12', 19 => '=13',
		20 => '=14', 21 => '=15', 22 => '=16', 23 => '=17', 24 => '=18',
		25 => '=19', 26 => '=1A', 27 => '=1B', 28 => '=1C', 29 => '=1D',
		30 => '=1E', 31 => '=1F', 32 => '=20', 33 => '=21', 34 => '=22',
		35 => '=23', 36 => '=24', 37 => '=25', 38 => '=26', 39 => '=27',
		40 => '=28', 41 => '=29', 42 => '=2A', 43 => '=2B', 44 => '=2C',
		45 => '=2D', 46 => '=2E', 47 => '=2F', 48 => '=30', 49 => '=31',
		50 => '=32', 51 => '=33', 52 => '=34', 53 => '=35', 54 => '=36',
		55 => '=37', 56 => '=38', 57 => '=39', 58 => '=3A', 59 => '=3B',
		60 => '=3C', 61 => '=3D', 62 => '=3E', 63 => '=3F', 64 => '=40',
		65 => '=41', 66 => '=42', 67 => '=43', 68 => '=44', 69 => '=45',
		70 => '=46', 71 => '=47', 72 => '=48', 73 => '=49', 74 => '=4A',
		75 => '=4B', 76 => '=4C', 77 => '=4D', 78 => '=4E', 79 => '=4F',
		80 => '=50', 81 => '=51', 82 => '=52', 83 => '=53', 84 => '=54',
		85 => '=55', 86 => '=56', 87 => '=57', 88 => '=58', 89 => '=59',
		90 => '=5A', 91 => '=5B', 92 => '=5C', 93 => '=5D', 94 => '=5E',
		95 => '=5F', 96 => '=60', 97 => '=61', 98 => '=62', 99 => '=63',
		100 => '=64', 101 => '=65', 102 => '=66', 103 => '=67', 104 => '=68',
		105 => '=69', 106 => '=6A', 107 => '=6B', 108 => '=6C', 109 => '=6D',
		110 => '=6E', 111 => '=6F', 112 => '=70', 113 => '=71', 114 => '=72',
		115 => '=73', 116 => '=74', 117 => '=75', 118 => '=76', 119 => '=77',
		120 => '=78', 121 => '=79', 122 => '=7A', 123 => '=7B', 124 => '=7C',
		125 => '=7D', 126 => '=7E', 127 => '=7F', 128 => '=80', 129 => '=81',
		130 => '=82', 131 => '=83', 132 => '=84', 133 => '=85', 134 => '=86',
		135 => '=87', 136 => '=88', 137 => '=89', 138 => '=8A', 139 => '=8B',
		140 => '=8C', 141 => '=8D', 142 => '=8E', 143 => '=8F', 144 => '=90',
		145 => '=91', 146 => '=92', 147 => '=93', 148 => '=94', 149 => '=95',
		150 => '=96', 151 => '=97', 152 => '=98', 153 => '=99', 154 => '=9A',
		155 => '=9B', 156 => '=9C', 157 => '=9D', 158 => '=9E', 159 => '=9F',
		160 => '=A0', 161 => '=A1', 162 => '=A2', 163 => '=A3', 164 => '=A4',
		165 => '=A5', 166 => '=A6', 167 => '=A7', 168 => '=A8', 169 => '=A9',
		170 => '=AA', 171 => '=AB', 172 => '=AC', 173 => '=AD', 174 => '=AE',
		175 => '=AF', 176 => '=B0', 177 => '=B1', 178 => '=B2', 179 => '=B3',
		180 => '=B4', 181 => '=B5', 182 => '=B6', 183 => '=B7', 184 => '=B8',
		185 => '=B9', 186 => '=BA', 187 => '=BB', 188 => '=BC', 189 => '=BD',
		190 => '=BE', 191 => '=BF', 192 => '=C0', 193 => '=C1', 194 => '=C2',
		195 => '=C3', 196 => '=C4', 197 => '=C5', 198 => '=C6', 199 => '=C7',
		200 => '=C8', 201 => '=C9', 202 => '=CA', 203 => '=CB', 204 => '=CC',
		205 => '=CD', 206 => '=CE', 207 => '=CF', 208 => '=D0', 209 => '=D1',
		210 => '=D2', 211 => '=D3', 212 => '=D4', 213 => '=D5', 214 => '=D6',
		215 => '=D7', 216 => '=D8', 217 => '=D9', 218 => '=DA', 219 => '=DB',
		220 => '=DC', 221 => '=DD', 222 => '=DE', 223 => '=DF', 224 => '=E0',
		225 => '=E1', 226 => '=E2', 227 => '=E3', 228 => '=E4', 229 => '=E5',
		230 => '=E6', 231 => '=E7', 232 => '=E8', 233 => '=E9', 234 => '=EA',
		235 => '=EB', 236 => '=EC', 237 => '=ED', 238 => '=EE', 239 => '=EF',
		240 => '=F0', 241 => '=F1', 242 => '=F2', 243 => '=F3', 244 => '=F4',
		245 => '=F5', 246 => '=F6', 247 => '=F7', 248 => '=F8', 249 => '=F9',
		250 => '=FA', 251 => '=FB', 252 => '=FC', 253 => '=FD', 254 => '=FE',
		255 => '=FF'
	);

	protected static $_safeMapShare = array();

	/**
	 * A map of non-encoded ascii characters.
	 *
	 * @var string[]
	 */
	protected $_safeMap = array();

	/**
	 * Creates a new QpEncoder for the given CharacterStream.
	 *
	 * @param Swift_CharacterStream $charStream to use for reading characters
	 * @param Swift_StreamFilter $filter if input should be canonicalized
	 */
	public function __construct(Swift_CharacterStream $charStream, Swift_StreamFilter $filter = null)
	{
		$this->_charStream = $charStream;
		if (!isset(self::$_safeMapShare[$this->getSafeMapShareId()])) {
			$this->initSafeMap();
			self::$_safeMapShare[$this->getSafeMapShareId()] = $this->_safeMap;
		} else {
			$this->_safeMap = self::$_safeMapShare[$this->getSafeMapShareId()];
		}
		$this->_filter = $filter;
	}

	public function __sleep()
	{
		return array('_charStream', '_filter');
	}

	public function __wakeup()
	{
		if (!isset(self::$_safeMapShare[$this->getSafeMapShareId()])) {
			$this->initSafeMap();
			self::$_safeMapShare[$this->getSafeMapShareId()] = $this->_safeMap;
		} else {
			$this->_safeMap = self::$_safeMapShare[$this->getSafeMapShareId()];
		}
	}

	protected function getSafeMapShareId()
	{
		return get_class($this);
	}

	protected function initSafeMap()
	{
		foreach (array_merge(
			         array(0x09, 0x20), range(0x21, 0x3C), range(0x3E, 0x7E)) as $byte) {
			$this->_safeMap[$byte] = chr($byte);
		}
	}

	/**
	 * Takes an unencoded string and produces a QP encoded string from it.
	 *
	 * QP encoded strings have a maximum line length of 76 characters.
	 * If the first line needs to be shorter, indicate the difference with
	 * $firstLineOffset.
	 *
	 * @param string $string to encode
	 * @param integer $firstLineOffset , optional
	 * @param integer $maxLineLength ,   optional 0 indicates the default of 76 chars
	 *
	 * @return string
	 */
	public function encodeString($string, $firstLineOffset = 0, $maxLineLength = 0)
	{
		if ($maxLineLength > 76 || $maxLineLength <= 0) {
			$maxLineLength = 76;
		}

		$thisLineLength = $maxLineLength - $firstLineOffset;

		$lines = array();
		$lNo = 0;
		$lines[$lNo] = '';
		$currentLine =& $lines[$lNo++];
		$size = $lineLen = 0;

		$this->_charStream->flushContents();
		$this->_charStream->importString($string);

		// Fetching more than 4 chars at one is slower, as is fetching fewer bytes
		// Conveniently 4 chars is the UTF-8 safe number since UTF-8 has up to 6
		// bytes per char and (6 * 4 * 3 = 72 chars per line) * =NN is 3 bytes
		while (false !== $bytes = $this->_nextSequence()) {
			// If we're filtering the input
			if (isset($this->_filter)) {
				// If we can't filter because we need more bytes
				while ($this->_filter->shouldBuffer($bytes)) {
					// Then collect bytes into the buffer
					if (false === $moreBytes = $this->_nextSequence(1)) {
						break;
					}

					foreach ($moreBytes as $b) {
						$bytes[] = $b;
					}
				}
				// And filter them
				$bytes = $this->_filter->filter($bytes);
			}

			$enc = $this->_encodeByteSequence($bytes, $size);
			if ($currentLine && $lineLen + $size >= $thisLineLength) {
				$lines[$lNo] = '';
				$currentLine =& $lines[$lNo++];
				$thisLineLength = $maxLineLength;
				$lineLen = 0;
			}
			$lineLen += $size;
			$currentLine .= $enc;
		}

		return $this->_standardize(implode("=\r\n", $lines));
	}

	/**
	 * Updates the charset used.
	 *
	 * @param string $charset
	 */
	public function charsetChanged($charset)
	{
		$this->_charStream->setCharacterSet($charset);
	}

	// -- Protected methods

	/**
	 * Encode the given byte array into a verbatim QP form.
	 *
	 * @param integer[] $bytes
	 * @param integer $size
	 *
	 * @return string
	 */
	protected function _encodeByteSequence(array $bytes, &$size)
	{
		$ret = '';
		$size = 0;
		foreach ($bytes as $b) {
			if (isset($this->_safeMap[$b])) {
				$ret .= $this->_safeMap[$b];
				++$size;
			} else {
				$ret .= self::$_qpMap[$b];
				$size += 3;
			}
		}

		return $ret;
	}

	/**
	 * Get the next sequence of bytes to read from the char stream.
	 *
	 * @param integer $size number of bytes to read
	 *
	 * @return integer[]
	 */
	protected function _nextSequence($size = 4)
	{
		return $this->_charStream->readBytes($size);
	}

	/**
	 * Make sure CRLF is correct and HT/SPACE are in valid places.
	 *
	 * @param string $string
	 *
	 * @return string
	 */
	protected function _standardize($string)
	{
		$string = str_replace(array("\t=0D=0A", " =0D=0A", "=0D=0A"),
			array("=09\r\n", "=20\r\n", "\r\n"), $string
		);
		switch ($end = ord(substr($string, -1))) {
			case 0x09:
			case 0x20:
				$string = substr_replace($string, self::$_qpMap[$end], -1);
		}

		return $string;
	}
}
